Q.32 Some of the cytokinins used in plant tissue
culture media are given below:
[P] ВАР
[Q Zeatin
[R] Kinetin
[S]2iP
Which of these are synthetic analogs?
(A) P and Q only
(B) Q and S only
(C) R and S only
(D) P and R only

Cytokinins promote cell division and shoot formation in plant tissue culture media. The question identifies synthetic analogs among BAP (P), Zeatin (Q), Kinetin (R), and 2iP (S).​

Question Breakdown

The options are [P] BAP (6-benzylaminopurine), [Q] Zeatin, [R] Kinetin (6-furfurylaminopurine), [S] 2iP (2-isopentenyladenine). Natural cytokinins occur in plants, while synthetic ones are lab-made for reliable use in media.​

Option Analysis

• (A) P and Q only: Incorrect. BAP is synthetic, but Zeatin is a natural cytokinin isolated from corn kernels.​

• (B) Q and S only: Incorrect. Zeatin and 2iP are both natural, derived from plant cytokinin pathways like isopentenyladenine derivatives.​

• (C) R and S only: Incorrect. Kinetin is synthetic (from aged DNA), but 2iP is natural.​

• (D) P and R only: Correct. BAP and Kinetin are synthetic analogs, widely used for stability and cost in tissue culture.​

Correct Answer

Option (D) P and R only. BAP and Kinetin mimic natural cytokinins but are artificially synthesized for consistent activity in media.​

Natural vs Synthetic Cytokinins

Natural cytokinins like Zeatin and 2iP come from plant tRNA or biosynthesis pathways. Synthetic ones like BAP and Kinetin offer better solubility and longevity.

This distinction matters for IIT JAM exams in biotechnology, as synthetic analogs dominate commercial protocols.​